We propose a longitudinal study beginning with 3-4 year old children, using an intensive naturalistic observational method to answer the following general questions: 1) Do children and parents from high Cardiovascular Disease (CVD) risk families differ from children and parents from low CVD risk families in regard to CVD risk ralated behaviors, CVD risk factors, or social influence attempts in regard to obseity or diet and exercise? 2) Why do some children become obese and others do not? 3) Why do some children develop cardiovascular risk factors and others do not? 4) do the variables or relationships among variables, above, vary by the age of the child, as the child becomes 7-8 years old? by gender of the child? by ethnicity of the family? or by the obesity of the parents? We propose to study a randomly selected sample of 3-4 year old children born on Galveston Island, stratified by the gender of the child and the ethnicity of the family. We will collect clinic data (blood pressures, resting pulse, height, weight, skinfolds and plasma cholesterol fractions, Type A behaviors) on the children at five times over the course of the five years in the project. During the four years between each of the elinic measurements, we will collect four days of observation data on the diet and exercise habits of the children and the social influence attempts. At the time of clinic assessment, we will also collect clinic data on parents of the child, and self report data on the parents diet and exercise habits and other psychosocial variables. This is a particularly important study because: 1) the observation methods will permit the most accurate assessment of the diet and exercise habits of the 3-4 year old children during this important four year phase in their development, where accurate self or parent report data is virtually impossible, and 2) it extends the observation of social influence categories (in regard to diet and exersise behaviors) to full day observations of child behavior on children from three ethnicities. We have also proposed two substudies. The first substudy will assess the energy expenditure levels (METs) of children in three age groups (3-4 yrs, 5-6 yrs, 7-8 yrs) and three body types (lean, average, obese) in 12 different activities, corresponding to the activity categories on the activity observation forms. The second substudy will determine how accurately mothers can provide a 24 hour recall on the diet and exercise behaviors of their 3-4 year old children, as compared to observational data on the same behaviors.